1. Technical Field
The present invention relates generally to a liquid ejecting apparatus such as an ink jet type printer and a control method thereof, and more particularly to a liquid ejecting apparatus having a heater that heats an ejection target, and a control method thereof.
2. Related Art
A typical liquid ejecting apparatus has a liquid ejecting head with nozzles operable to eject various liquids. As a representative example of a liquid ejecting apparatus, for example, image recording apparatuses can be given such as ink jet type printers (hereinafter simply referred to as printers), which are provided with ink jet type recording heads (hereinafter simply referred to as recording heads and can also be referred to as liquid ejecting heads which eject ink in the form of a liquid) and perform recording of an image or the like by ejecting and landing ink in the form of liquids from nozzles of the recording head onto a recording medium (an landing target) such as recording paper. Liquid ejecting apparatus are not limited to image recording. For example, in recent years, liquid ejecting apparatus have also been used in manufacturing, such as in manufacturing of a color filter of a liquid crystal display or the like.
Recently, printers have been used for instances of performing printing on recording media larger than the printing paper typically used with a general home printer, for example, outdoor advertisements or the like. As the recording medium in this case, a resin film made of, for example, vinyl chloride can be used to provide weather resistance. A solvent ink containing an organic solvent as its main component can be used to print on such a resin film. The solvent ink is excellent in scratch resistance and weather resistance, compared to water-based ink.
Incidentally, since it is hard for the resin film to absorb ink, there is a risk of a recorded image bleeding. In order to cope with such a problem, the use of a heater (a platen heater) to heat a recording medium on a platen has been proposed, in which drying and fixing of ink landed on recording paper are promoted by heating of the recording paper by the heater (refer to JP-A-2010-30313, for example).
In the case of printing an advertisement or the like that is even larger than the maximum size of a recording medium capable of being printed by a printer, the advertisement can be partially printed on a roll-shaped film, the film cut and divided after printing into the respective parts, and the respective parts can be joined together, thereby creating one sheet of continuous finished product. When, however, a recording medium is heated by the above-described heater, heat from the heater is transmitted to a recording head, whereby the viscosity of the ink changes over time. In general, an increase in temperature of the inside of the recording head lowers the viscosity of the ink. If the viscosity of the ink is lowered, the amount (weight or volume) of ink ejected at a given pressure is increased. That is, the ejection characteristics change in accordance with the temperature. Accordingly, there is a risk of the density of an image printed on the film vary undesirably. As described above, where respective printed parts of an image are joined into one sheet, there is a problem where differences in density are conspicuous at the boundary portions, thereby resulting in poor image quality. And when the temperature of the inside of the recording head is low at the start of the printing relative to the steady state temperature of the recording head, the resulting temperature change can easily cause the above-mentioned problem.